This is a proposed continuation of an NIMH Research Scientist Award to provide salary support to continue projects that have already received separate grant support that deal with studies pertinent to synaptic transmission in the mammalian brain, with an emphasis on experiments aimed at increasing understanding of the pharmacology of antipsychotic agents and other psychotropic agents that interact with dopamine receptor sites in forebrain. The projects include studies of basic properties of sites that may represent dopamine receptors, especially those represented by high-affinity labeling with dopamine agonists; the evalution of complex dopamine analogs as probes of the chemical characteristics of dopamine receptor surfaces; the development and evaluation of novel dopamine analogs with agonist and regionally selective antagonist properties that may lead to clinically useful, novel psychotropic agents; the assessment of dopamine receptor properties as a function of developing and aging; and exploration of pharmacologic properties of available neuroleptic-antipsychotic agents as functions of development and age, of the circadian cycle, and of time following treatment, with behavioral and biochemical as well as some pharmacokinetic correlates in laboratory rodents and human subjects.